The present invention relates to the field of vehicle seating technology. More particularly, the invention relates to enhancements in lift structures for motor vehicle seating.
Typically, a lift structure for a vehicle seat includes a floor bracket and an upper support, such as a seat cushion frame, which is height-adjustably connected to the floor bracket or track sections. A torsion tube typically couples a height-adjustable upper support on each side of the vehicle seat so that the sides of the lift structure are parallel when the vehicle seat is subjected to a normal load.
Additionally, a vehicle seat typically has a lap belt restraint as part of a three point harness. The lap belt restraint is typically attached to the floor bracket, which is also referred to as a pivot bracket. The method of attachment to the pivot bracket that is typically employed for a height-adjustable vehicle seat, such as a vehicle seat with a lift structure, may result in discomfort for an occupant of the vehicle seat and may potentially result in miscommunication between sensors of a lift structure.
One noted problem that may occur when a lift structure of a vehicle seat is activated to adjust the seat height is that the seatbelt of the vehicle seat may tighten around the seat occupant. Such a tightening typically results in discomfort for the seat occupant and may require occupant to adjust the seatbelt. A second problem may occur when a lift system of a vehicle seat is activated, wherein the seatbelt may become cinched, since the seatbelt restraint is attached to a floor-mounted pivot bracket. A third problem may result when a sensor, such as an Occupant Classification Sensor (OCS), is located between the occupant and the seatbelt attachment. In this case, the cinched seatbelt may contribute to false inputs being delivered to the OCS. In many vehicle seats, height adjustment of the upper support is typically performed manually or by a motor. Additionally, attaching a lap belt restraint to the upper support of a vehicle seat base is known in the art. However, in addition to the above-stated problems, the attachment of a lap belt restraint to the upper support may create problems with properly restraining and reinforcing the load of the vehicle seat. Becker et al., U.S. Patent Publication No. 2003/0160483, assigned to C. Rob. Hammerstein GmbH & Co., proposes one design to address this issue; however, such a design is itself costly and complicated.
Accordingly, it would be advantageous to provide a lift structure of a vehicle seat, wherein the restraint attachment is affixed to or moves accordingly with an upper support of the vehicle seat base. Such a lift structure would permit movement of the restraint attachment with the height adjustment of the vehicle seat, thus reducing the potential for discomfort for the vehicle seat occupant. The relocation of the restraint attachment to the upper support addresses the aforementioned comfort issue, in addition to avoiding the false inputs being delivered to the OCS system. Additionally, it would be advantageous to provide a lift structure, wherein the seatbelt loads on the upper support of the vehicle seat base bypass the linkages and transfer the seatbelt loads to the pivot bracket through a load transfer link. It should be appreciated that the teachings herein may be applied without necessarily achieving any the advantages identified herein.